[NukeNet] Utility Will Use Batteries to Store Wind Power

[Mike Ewall]

http://www.nytimes.com/2007/09/11/business/11battery.html

Utility Will Use Batteries to Store Wind Power

By MATTHEW L. WALD
Published: September 11, 2007

WASHINGTON, Sept. 10 ­ American Electric Power, a coal-burning 
utility company that is looking for ways to connect more wind power 
to its grid, plans to announce on Tuesday that it will install huge 
banks of high-technology batteries.

The batteries are costly and their use at such a big scale has not 
been demonstrated, but they may be an essential complement to 
renewable power, experts say.

"We're looking at what we believe the grid of the future is going to 
be," said Carl L. English, president of A.E.P. "We're going to need a 
significant amount of storage if for no other reason than to take 
greatest advantage of alternative energy sources like wind power."

The investment would position the company well if any of the 11 
states in its service territory establish a minimum quota for 
renewable energy, or if Congress sets a national standard, company 
executives said; it would also help if carbon controls were 
instituted and wind power were to gain a financial advantage over coal.

An expert not involved in the program, Edgar DeMeo of Renewable 
Energy Consulting Services, said, "They must think there's enough 
potential there so they want get a better handle on how it works." 
But Mr. DeMeo and others said that wind energy had substantial room 
to grow before storage became necessary.

American Electric Power's batteries will be used to smooth the power 
delivery from wind turbines. They can charge at night, when the wind 
is strong but prices are low, and give the electricity back the next 
afternoon, when there is hardly any wind but power prices are many 
times higher, company officials said. That strategy would reduce the 
amount of power generated from inefficient peak-demand units.

The batteries can also insert energy into the grid during brief 
voltage drops, reducing the chance of a blackout and stabilizing the 
grid for all users. They may also delay or eliminate the need for 
transmission upgrades in some areas, the company said.

At least at this stage, saving money by storing a windmill's 
production for peak-price hours will be difficult. The cost is very 
high, $27 million for six megawatts of capacity, or about $4,500 a 
kilowatt, including the price of substation improvements. Building a 
gas turbine of that size to meet peak needs would cost substantially 
less. But the battery system would be able to store power made from 
wind, a form of generation that does not produce any carbon dioxide.

The batteries can each deliver one megawatt of power ­ enough to run 
a medium-size shopping center ­ for a little more than seven hours. 
Replenished nightly, they give back about 80 percent of the 
electricity put into them. Each is the size of a double-decker bus, 
and installation is not permanent; they can be moved to another site 
as the need arises.

The batteries will be built by NGK Insulators Ltd. of Japan. They use 
a sodium sulfur chemistry and operate at temperatures of more than 
800 degrees Fahrenheit.

And while the batteries are large by the standards of previous 
installations, they are small relative to wind production; one 
battery would hold about as much energy as a single large wind 
machine could produce in a day, Mr. DeMeo pointed out. And they are 
small relative to total energy demand.

But, he said, "If we ever really do get cheap storage, and that's a 
possibility, that's a game changer."

A.E.P. intends to have 1,000 megawatts of energy storage on its 
system in the next decade, according to the company, and at least 25 
megawatts from batteries of this type.

A range of options is available for the remainder of the storage, 
including the use of plug-in hybrid cars, Mr. English said. The idea 
behind plug-in hybrids is that the owner of a car would charge the 
batteries every night when demand and cost of electricity were low. 
The next day, under a contract between the utility company and the 
driver, the car would be left plugged when not in use, and the power 
company could reverse the flow of electricity and draw power out of 
its batteries during times of peak demand. Enough power would be left 
in the batteries to start the engine, so that a driver returning to a 
drained car could still run it on gasoline until the batteries could 
be charged again at night. It would take more than 1,000 such 
vehicles to equal one of the sodium-sulfur batteries, however.